The popularity of partially cooked, ready-to prepare products has increased over the years due to the ease of end consumer preparation and continued improvements in product quality. Examples of partially cooked, ready-to-prepare products include flour-based products, which can be partially cooked by the manufacturer. The end consumer can then complete the cooking process in less time and effort than it would take to make the product from scratch, but can still achieve results similar to a made-from-scratch product.
When a product containing flour is heated, such as during cooking of the product, the starch and protein components of the flour begin chemical and physical transformations. These transformations help to provide the structure and texture of the cooked product. Additionally, heating a flour-based product drives off some of the moisture contained in the flour as well as some of the water which was added to make the flour-based product. The loss of moisture combined with the starch and protein reactions can cause the flour based product to attain a rigidity during the heating process.
It is desirable, with partially cooked products, to provide the end consumer with a product which, when finally cooked, will attain the texture and structure of a fully cooked product made from scratch. In addition, for some partially cooked products, it is desirable to provide the end consumer with a product that is sufficiently flexible such that it can be formed into a desired shape, and even filled or topped with additional ingredients, prior to the final cooking step.
An example of a flour-based product that can be partially cooked by the manufacturer for subsequent forming and final cooking by the end consumer is a food shell, such as a tortilla. Food shells can be used to make various products by combining them with other ingredients to make products such as tacos, quesadillas, flautas, burritos, taco salad shells, taco or tortilla chips, pizzas, enchiladas, piroshkis, stuffed sandwiches, egg rolls, snack food rolls, samosas, taquitas and the like.
Methods for forming flour-based food items such as tortillas, tacos and the like are known in the art. Traditional methods of making tortillas utilize some form of a baking step in combination with additional cooking steps to provide the desired finished product texture and structure.
An example of a known method for the production of a sheeted dough is U.S. Pat. No. 4,950,490, which provides a rigid, friable taco shell from sheeted dough which is partially cooked by frying in fat. The taco shell has a delaminated portion which comprises at least 60% of the taco surface area. The taco shell further comprises at least 4% volatilizable plasticizer, less than 35% total plasticizer and flour that is at least 50% corn flour.
To make a flexible partially cooked product, some sort of post-cooking or post-frying treatment step is also required to provide suitable flexibility to the product. The post-cooking or post-frying step typically includes some sort of hydration or treatment with a plasticizer, and may be combined with a reheating step before the final cooking step.
U.S. Pat. No. 3,930,049 discloses a process for preparing a shelf-stable, flexible tortilla. The process comprises the steps of: (a) lightly frying a hot, pre-baked tortilla to retain 13.5% moisture and sterilize the tortilla, (b) maintaining the fried sterile tortilla at an elevated temperature, and (c) packaging and sealing the fried sterile tortilla in a moisture-proof container. The tortilla is boiled in the container by the end consumer to attain the desired flexibility.
U.S. Pat. No. 4,781,932 discloses a food shell and method of manufacture. The shell comprises more than 25% starch, 20-38% non-volatilizable plasticizer and at least one delaminated portion which comprises more than 60% of the surface area. The shell further comprises a plasticizer and softening agent in the range of 28%-60%. The shell is partially baked (known as par-baked), then fried until the dough is rigid, and finally misted with a softening agent, such as water.
U.S. Pat. No. 4,735,811 discloses a baked tortilla and method of manufacture. The tortilla comprises at least 25% starch, 25-55% plasticizer, with water (less than 25% after cooking), and more than 1.5 water holding capacity.
Fried dough with moisture contents below about 10 wt-% result in a dough product which is rigid. Previous attempts to provide a cooked dough product that is flexible have involved some form of post-cooking treatment to return flexibility to the cooked dough product. An example is U.S. Pat. No. 4,781,932, which adds moisture to the dough after it is baked and fried by misting the rigid cooked dough with a plasticizing agent, such as water. By adding water after the product has been cooked to rigidity, the product can have a moisture content ranging from 8-22%, thereby making it flexible again. Another example is U.S. Pat. No. 3,930,049, in which the cooked dough sealed in a moisture proof container is heated in boiling water by the end consumer to render the product suitably flexible. The consumer then prepares the heated dough product and finishes it by baking.
There is a continuing need for processes for preparing partially cooked food products, such as partially fried food shells, that remain flexible and can be subsequently formed and finally cooked to attain the desired organoleptic qualities.